I tried to make an aluminum servo horn by myself and used it for 2 mm thread cutting, the tip was broken and clogged at the second thread cutting. Every recovery I tried to reopen failed and eventually it will not be usable. Since aluminum is fixed to the cutting edge, the mini-milling cutter cut hands to cut off cutting oil carefully so as not to apply unreasonable force, but bought a high tap to cover his immaturity Sorry for this result.